The Hidden Blade Assassin's Creed in Depth

Airwalk to air assassinate is made possible by the throwing knife glitch (it has been patched, so you would have to delete the update to still use it). Basically start airwalking and when an enemy is in range (locking on isn't required) switch to your hidden blade(s) using the weapon wheel and mash the attack button to air assassinate when getting out of the weapon wheel.

This is demonstrated on some targets. First the Pazzi conspirators, excluding Stephano da Bagnone who was a challenge to air assassinate since he walked under a building roof throughout his entire travel route.

Bernardo Baroncelli is simple enough. Airwalk from a nearby roof into his path.

The setup for Francesco Salviati is about the same as for the stunt IanXO4 did a while back.
http://thehiddenblade.com/francesco-salviati-assassination-variety-pack

For Antonio Maffei I use the airwalk glitch as a shortcut reaching the tower the target's on. At the start of the mission climb up the nearby tower and airwalk in the direction of the target. Now this causes an inconsistency in the game because the mercenary tells Ezio that Antonio Maffei is on the city's tallest structure, and yet the tower you airwalk from is a little higher. The actual assassination doesn't end in an air assassination because you get seen before reaching the target, causing him to jump to the railing where he can't be assassinated while in a crouching position.

Francesco de' Pazzi is used as an example of air tackling since he can't be air assassinated. And speaking of which I had some stuff recorded I put in this video since that was the only way it would see the light of day. I had investigated a possible Early Death on Francesco right before the assassination, but it failed.